Husqvarna K770 SmartGuard Instruction manual

Workshop manual
K770 SmartGuard
English
1453 - 001 - 02.04.2020

Contents
1 Introduction
1.1 Document description............................................ 3
1.2 Target group...........................................................3
1.3 Revisions................................................................3
1.4 Safety..................................................................... 3
1.5 Servicing tools........................................................3
2 Safety
2.1 Safety definitions....................................................4
2.2 General safety instructions.....................................4
2.3 Symbols on the product......................................... 4
3 Servicing data
3.1 Symbols in the diagrams........................................5
3.2 Tightening torques................................................. 6
4 Servicing tools
4.1 Servicing tools overview.......................................10
4.2 Servicing tools overview.......................................11
4.3 Servicing tools overview.......................................12
5 Product overview for repair and servicing
5.1 Components.........................................................13
5.2 Basic modules of the product...............................14
6 Repair and servicing
6.1 Starter.................................................................. 22
6.2 Ignition system..................................................... 25
6.3 Flywheel............................................................... 29
6.4 Air filter................................................................. 30
6.5 Fuel system..........................................................31
6.6 Carburetor............................................................ 33
6.7 Decompression valve...........................................42
6.8 Cylinder and piston.............................................. 43
6.9 Piston wear.......................................................... 46
6.10 To assemble the piston...................................... 47
6.11 To assemble the cylinder................................... 48
6.12 Crankcase.......................................................... 48
6.13 Clutch................................................................. 54
6.14 Cutting head.......................................................57
6.15 Wet system........................................................ 65
6.16 Throttle trigger and throttle trigger lockout......... 67
6.17 OilGuard.............................................................68
7 Troubleshooting
7.1 Engine does not start........................................... 70
7.2 Engine stops during operation - no sparks...........71
7.3 Engine stops during operation............................. 71
7.4 Weak output or change of speed......................... 72
7.5 Other engine problems.........................................72
8 Wiring diagram
8.1 Wiring diagram OilGuard......................................73
21453 - 001 - 02.04.2020

1 Introduction
1.1 Document description
This manual gives a full description of how to do
maintenance and repair on the product. It also gives
safety instructions that the personnel must obey.
1.2 Target group
This manual is for personnel with a general knowledge
of how to do repair and do servicing. All personnel that
do repair or do servicing on the product must read and
understand the manual.
1.3 Revisions
Changes to the product can cause changes to the
maintenance work and spare parts. Separate
information is sent out for each change.
Read the manual together with all received information
about changes to maintenance and spare parts for the
product.
1.4 Safety
WARNING: All personnel that repair or do
servicing on the product must read and
understand the safety instructions in this
workshop manual.
1.5 Servicing tools
The manual gives information about necessary servicing
tools. Always use original tools from Husqvarna.
1453 - 001 - 02.04.2020 Introduction - 3

2 Safety
2.1 Safety definitions
The definitions below give the level of severity for each
signal word.
WARNING: Injury to persons.
CAUTION: Damage to the product.
Note: This information makes the product easier to use.
2.2 General safety instructions
• Do not repair the product unless you have read and
understood this workshop manual.
• The service center where the product is repaired
must have safety equipment approved by local
bylaws.
• The product is examined and approved only with the
equipment given or recommended by the
manufacturer.
• Prevent health and safety risks. All personnel must
obey laws and requirements when they do the
procedures given in this manual.
• Obey the local waste regulations.
• Always make sure that all nuts and bolts are
correctly tightened.
• Use protective gloves and eye protection. Goggles
must obey the ANSI Z87.1 for US or EN166 for EU
countries.
• When using compressed air, do not point it to your
body. Air can go into the bloodstream.
• Use hearing protection when the engine is started.
• The product can make sparks and cause ignition of
flammable materials.
• Replace all damaged or missing warning symbol
decals.
• Gasoline and its fumes are poisonous.
• Gasoline can cause damage to the eyes and the
skin.
• Gasoline can cause breathing problems.
• Gasoline is flammable.
2.3 Symbols on the product
WARNING: This product can be
dangerous and cause serious injury or
death to the operator or others. Be careful
and use the product correctly.
Read the operator's manual carefully and
make sure that you understand the
instructions before you use this product.
Use approved protective helmet, hearing
protection, eye protection and respiratory
protection.
This product complies with applicable EC
Directives.
Dust forms when cutting. The dust can
cause injuries if inhaled. Use an approved
respiratory protection. Avoid inhaling
exhaust fumes. Always provide for good
ventilation.
WARNING! Kickbacks can be sudden,
rapid and violent and can cause life
threatening injuries.
Sparks from the cutting blade can cause
fire in fuel, wood, clothes, dry grass or
other flammable materials.
Make sure that the cutting blade does not
have cracks or other damages.
Do not use circular saw blades.
Choke
Air purge bulb
Decompression valve
Starter rope handle
Use a fuel mixture of gasoline and oil.
Note: Other symbols/decals on the product refer to
special certification requirements for some markets.
4 - Safety 1453 - 001 - 02.04.2020

3 Servicing data
3.1 Symbols in the diagrams
Tightening torque, Nm
1453 - 001 - 02.04.2020 Servicing data - 5

3.2 Tightening torques
3-5
4-6
4-6
4-6
2,0
7-9
3-5
4-6
6 - Servicing data 1453 - 001 - 02.04.2020

11-12
10-12
5-7
11-13
11-13
11-13
7-9
17-23
1453 - 001 - 02.04.2020 Servicing data - 7

25-30
1-1.5
9-11
1-1.5
38-42
14-16
4-10
6-8
6-8
14-16
0.5-0.8
4-6
5-7
8-10
8 - Servicing data 1453 - 001 - 02.04.2020

13
6-8
20-25
5
5-6
10-12
6
6
4
3
5-7
5
6-8 25-30
9-11
1453 - 001 - 02.04.2020 Servicing data - 9

4 Servicing tools
4.1 Servicing tools overview
0,3 mm
1 2 3
4 5 6
7 8 9
Po-
si-
tion
Designation Used for Order No./
Source
1 Air clearance gauge To adjust the air clearance between the ignition module and the fly-
wheel.
502 51 34-02
2 Assembly punch To assemble the sealing rings of the crankshaft in the crankcase. 502 50 82-01
3 Bearing press To disassemble the primary bearing and assemble the crankshaft. 544 10 36-02
4 Bearing press To assemble the primary bearing and assemble and disassemble
blade shaft bearing and axle.
506 37 61-02
5 Bearing puller Remove the primary bearing from the crankshaft. 531 00 48-67
6 Combination wrench General. 506 38 26-01
7 Compression tester To examine the compression in the cylinder. 531 03 16-86
8 Bearing press To disassemble and assemble the clutch drum ball bearing. 504 56 79-01
9 Cylinder seal To examine the crankcase for leaks. 544 10 33-01
10 - Servicing tools 1453 - 001 - 02.04.2020